Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/10—Homopolymers or copolymers of propene
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/022—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the choice of material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/06—Rod-shaped
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/269—Extrusion in non-steady condition, e.g. start-up or shut-down
  • B29C48/2694—Intermittent extrusion
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/285—Feeding the extrusion material to the extruder
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K7/00—Use of ingredients characterised by shape
  • C08K7/02—Fibres or whiskers
  • C08K7/04—Fibres or whiskers inorganic
  • C08K7/14—Glass
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K9/00—Use of pretreated ingredients
  • C08K9/04—Ingredients treated with organic substances
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/06—Polyethene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L95/00—Compositions of bituminous materials, e.g. asphalt, tar, pitch
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
  • E01B3/00—Transverse or longitudinal sleepers; Other means resting directly on the ballastway for supporting rails
  • E01B3/44—Transverse or longitudinal sleepers; Other means resting directly on the ballastway for supporting rails made from other materials only if the material is essential
• • E—FIXED CONSTRUCTIONS
  • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
  • E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
  • E01B3/00—Transverse or longitudinal sleepers; Other means resting directly on the ballastway for supporting rails
  • E01B3/46—Transverse or longitudinal sleepers; Other means resting directly on the ballastway for supporting rails made from different materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/001—Combinations of extrusion moulding with other shaping operations
  • B29C48/0018—Combinations of extrusion moulding with other shaping operations combined with shaping by orienting, stretching or shrinking, e.g. film blowing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
  • B29C48/12—Articles with an irregular circumference when viewed in cross-section, e.g. window profiles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/15—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor incorporating preformed parts or layers, e.g. extrusion moulding around inserts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/16—Articles comprising two or more components, e.g. co-extruded layers
  • B29C48/18—Articles comprising two or more components, e.g. co-extruded layers the components being layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/285—Feeding the extrusion material to the extruder
  • B29C48/288—Feeding the extrusion material to the extruder in solid form, e.g. powder or granules
  • B29C48/2886—Feeding the extrusion material to the extruder in solid form, e.g. powder or granules of fibrous, filamentary or filling materials, e.g. thin fibrous reinforcements or fillers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
  • B29C48/25—Component parts, details or accessories; Auxiliary operations
  • B29C48/285—Feeding the extrusion material to the extruder
  • B29C48/297—Feeding the extrusion material to the extruder at several locations, e.g. using several hoppers or using a separate additive feeding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2095/00—Use of bituminous materials as moulding material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/06—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts
  • B29K2105/12—Condition, form or state of moulded material or of the material to be shaped containing reinforcements, fillers or inserts of short lengths, e.g. chopped filaments, staple fibres or bristles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
  • B29K2105/26—Scrap or recycled material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2709/00—Use of inorganic materials not provided for in groups B29K2703/00 - B29K2707/00, for preformed parts, e.g. for inserts
  • B29K2709/08—Glass
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
  • B29L2031/00—Other particular articles
  • B29L2031/06—Rods, e.g. connecting rods, rails, stakes

Definitions

• This invention relates to novel material compositions for railway ties and to methods for the fabrication thereof.
• Rail ties which are used to support railway tracks on a roadbed of ballast or concrete, are typically made of wood. Wood is the generally preferred constituent material because it can withstand climatic changes, and wooden ties are relatively easy to install and replace. Since thousands of miles of railway tracks are in use throughout the world, a vast number of railway ties is needed each year to replace those which have been worn out over time.
• wooden railway ties provide durability and withstand well the static and dynamic loads of freight and passenger trains, they are susceptible to attack from fungi and Insects which will weaken and eventually deteriorate the railway ties.
• the lifespan of wooden railway ties can be prolonged by the use of preservatives, in particular creosote, but such preservatives result in potential environmental hazards, both during the treatment procedure for the manufacture of ties, and by reason of leaching of creosote into the surrounding soil and the water table in the region of the railroad.
• preservatives in particular creosote
• U.S. Patent No. 4,405,727 patented September 20, 1983 by T. F. Brownscombe is directed to reinforced polymer compositions.
• Such polymer reinforcing material consisted of a particulate mineral material, e.g., silicates, aluminosilicates, glasses, mica, talc, clays, bentonites, kaolins, vermiculite, asbestos, calcium silicates, wollastonite silica and alumina, having, as reactive surface sites, oxygen atoms or hydroxy!
• atoms or a filamentary mineral material, e.g., standard glass fibers, chopped or continuous or milled or natural fibrous materials, e.g., asbestos, having a very thin film of organic molecules, e.g., polypropylenes, polyethylenes, S-B-S thermoplastic elastomers, poly-l-butene, poly(vinyl arene) homopolymers and copolymers polystyrene, ABS SAN, polyesters, polybutylene terephthalate, polyethylene terephthalate poly(phenoxy) poly(aryl ether) nylons and polyurethanes which are chemically bonded to its surface.
• U.S. Patent No. 5,367,007 discloses a multi-layer molded composite paving block.
• the first layer of the multilayer molded composite paving block was formed from recycled asphalt, a thermosetting or thermosetting synthetic plastic, a monofilament fibre material and an elastic material.
• the second layer of the multi-layer molded composite paving block was formed from a synthetic thermoplastic material, e.g., polyethylene or a thermosetting synthetic plastic and an aggregate material.
• the synthetic plastic material of each of the layers was heated and was sure bonded to one another. This forms an interlocked structural interface to provide a single integral block.
• the binding constituent was a synthetic plastic material and the aggregate material was in the form of irregular multi-faceted pieces, e.g., gravel limestone or granite.
• the binding constituent held the aggregate material together.
• the railway tie may also include an inner strengthening core of high tensile strength material.
• There is no explicit or implicit teaching of a composition comprising asphalt and a mixture of glass fibre-filled polypropylene and high density and/or low density polyethylene.
• U.S. Patent No. 5,722,589 patented March 3, 1998 by Richards, provides a composite load bearing structure including a main body portion made of a binding constituent and an aggregate material.
• the structure included an inner strengthening member of high tensile strength material within the body.
• Such an inner strengthening member comprised reinforcing bars, rolled drawn or cast ferrous sections, rolled drawn or cast composite alloy sections, plastic metallic or carbon based fibres, wire mesh or expanded metal mesh.
• U.S. Patent No. 5,789,477 patented August 4, 1998 by Nosker, provides a composite building material formed from recyclable waste.
• the composite material comprised a mixture of high-density polyethylene and a thermoplastic-coated fibre, e.g., glass fibres.
• U.S. Patent No. 6,191,228, patented February 20, 2001 by Nosker provides a railway tie formed from a synthetic plastic composite material.
• Such plastic composite material included a polystyrene component forming a first phase and a polyolef ⁇ n component forming a second phase.
• Such two phases intertwine and remain continuous throughout the composite railway tie.
• U.S. Patent No. 6,247,651 patented June 19, 2001 by Marinelli, provides a railway tie shaped like an I-beam made from a combination of recycled materials.
• Such combination of recycled materials was composed of recycled high- density polyethylene and polypropylene, scrapped and granulated rubber tires and screened waste glass fibres
• U.S. Patent No. 7,122,594 patented Oct. 17, 2006 by N. Kubo et al is directed to modified block copolymer compositions.
• Such compositions consisted of a mixture of a particular block copolymer, e.g., of vinyl aromatic hydrocarbons and conjugated dienes and a suitable filler, e.g., silica-based inorganic fillers, metal oxides and metal hydroxides.
• composition comprises an elastomeric precursor e.g., poly (dimethylsiloxane) poly ⁇ soprene, polybutadiene, poly ⁇ sobutylene, etc.
• elastomeric precursor e.g., poly (dimethylsiloxane) poly ⁇ soprene, polybutadiene, poly ⁇ sobutylene, etc.
• compositions and methods of manufacture for providing railway ties which are not susceptible to damage from harsh weather conditions and excessive sunlight; not susceptible to attack from fungi and insects which weaken and eventually deteriorate the railway ties; which are free of preservatives, e.g., creosote, which can result in environmental hazards; and which are composed of substantially recycled materials having a lower polymer/plastic content than many current alternative railway ties.
• the invention provides in a first aspect an extrudable composition suitable for the forming of railway ties and other articles requiring the ability to support the high loads and impacts encountered in use.
• Composites according to this aspect comprise (A) from about 20 % to about 85% by weight of an asphaltic portion, and (B) correspondingly, from about 80% to about 15% by weight of a polymeric portion comprising a mixture of (i) a recyclable plastic and (ii) a strengthening mixture made up of virgin or recycled polypropylene or a functionally equivalent synthetic polymer reinforced by the inclusion of glass fibres, fibres which are functionally equivalent to glass fibres; or functionally similar reinforcing agents.
• a railway tie which is formed from a composition according to the invention as aforesaid by molding.
• a railway tie having a first portion formed of a first selected composition according to the invention and a second portion formed from a second selected composition according to the invention.
• the present invention in a still further aspect is directed to a method for producing a railway tie having a first portion and a second portion of differing composition, by charging the first channel of a dual material die with a first composition according to the invention and the second channel of the dual material die with the second composition according to the invention, then pumping the two mixtures through the dual material die into a flow mold to shape and cool the composite into a railway tie
• the single drawing Figure illustrates the process according to the invention for preparing a composite article, such as a railway tie, having a first region made of a first synthetic asphalt/plastic material of the present invention ("Formula 1") and a second region made of a second formulation of this kind (“Formula II").
• Forma 1 refers to the composition which makes up a portion of the railway tie which is of special strength and durability and Is disposed within the strategically-located area of the railway tie where fasteners are to be located. This could, for example, be a central core section of the formed railway tie.
• the balance of the railway tie is composed of a "standard mix” identified as Formula II, a less costly material than Formula II, but having properties which are more than adequate for its intended use.
• the extruded products of Formulas I and II could be in horizontally layered cross-sections of the composite article.
• extrudable asphalt/plastic compositions comprise (A) an asphaltic portion and (B) a polymeric composition which itself is made up of a mixture of (i) a recyclable plastic and (ii) a strengthening mixture.
• plastics refers to various organic compounds produced by polymerization, capable of being molded, extruded, cast into various shapes, including polymer or recycled thermoplastic material.
• the recyclable plastic component may be selected from a wide range of readily available, potentially waste products. As examples:
• Breaking strengths in a three-point flexure test (on a 6" span of fabricated railway tie) exhibited breaking strengths generally in a range from 1600-2000 p.s.i. or greater.
• a wide variety of possible polymeric materials and strengtheners were found to produce good results when the weight ratio of asphalt ⁇ c portion/recyclable plastic/strengthening mixture was 75%/12,5%/12.5%
• Formula I the "strengthened mix" in DUROPARTM formulations contains from 15% to 75% asphaltic material and from 85% to 25% of a first polymeric composition, which itself is comprised of (i) about 50% recyclable thermoplastic material (hereinafter “Formula I, Part 2(i)”) and ( ⁇ ) about 50% of a glass fibre-filled recyclable thermoplastic material, such as a glass fibre-filled polypropylene, as strengthening agent, or with an alternative filler of equivalent strengthening effect(hereinafter "Formula 1, Part 2( ⁇ )").
• a first polymeric composition which itself is comprised of (i) about 50% recyclable thermoplastic material (hereinafter “Formula I, Part 2(i)") and ( ⁇ ) about 50% of a glass fibre-filled recyclable thermoplastic material, such as a glass fibre-filled polypropylene, as strengthening agent, or with an alternative filler of equivalent strengthening effect(hereinafter "Formula 1, Part 2( ⁇ )").
• Exemplary Formula I embodiments include, without limitation, compositions with ranges of (a) 65- 75%/35-25% (asphaltic material/first polymeric composition) and (b) 70 -75%/ 12- 15%/12-15% (asphaltic material/Formula I, Part 2( ⁇ )/Formula I, Part 2( ⁇ i)).
• Formula II in DUROPARTM formulations comprises from about 20% to about 85% by weight of an asphalt ⁇ c portion and from about 15% to about 80% by weight of a second polymeric portion comprising (i) recyclable thermoplastic material (hereinafter "Formula II, Part 2( ⁇ )”) and ( ⁇ ) optionally a glass fibre-filled recyclable thermoplastic material as a strengthening agent, or with an alternative filler of equivalent strengthening effect(here ⁇ nafter "Formula II, Part 2(ii)").
• a second polymeric portion comprising (i) recyclable thermoplastic material (hereinafter “Formula II, Part 2( ⁇ )”) and ( ⁇ ) optionally a glass fibre-filled recyclable thermoplastic material as a strengthening agent, or with an alternative filler of equivalent strengthening effect(here ⁇ nafter "Formula II, Part 2(ii)").
• Exemplary Formula II embodiments include, without limitation, compositions with ranges of (a) 70-80%/30-20% (asphaltic material/second polymeric composition) and (b) 73-77%/12-15%/12-15% (asphaltic material/ Formula II, Part 2(i)/Formula II, Part 2( ⁇ )).
• about 50% of the strengthening agent is used.
• less than, but up to 50% of the strengthening agent may be used, depending on the desired strength of the overall formulation. Of course, more than 50% of the strengthening agent may also be used.
• the asphaltic portion may be a conventional mixture of asphalt binder and aggregate. It is preferred, however, that the asphaltic portion which Is mixed with the plastic portion in preparing a charge of Formula I or Formula II be made up of asphalt particles of a size such that at least 75% of such particles would pass through a screen having 0.50" square openings.
• a suitable material for this purpose are 3/8" and/or 1/4" fines of asphalt readily available from asphalt manufacturers.
• thermoplastic material is used in the description and claims herein, it will be understood to include the materials listed above as potential waste products. However, virgin or recycled polypropylene or polyethylene (high-density and/or low-density), or other thermoplastic material, may be substituted if recycled materials are not available.
• the aforementioned strengthening agent is preferably glass fibre-filled high-density polypropylene.
• Composite blocks in the shape of railway ties formulated from asphaltic/plastic compositions according to the present invention may be manufactured in a number of ways.
• the composition may be heated to workable condition (250 - 400° F) and molded under a suitable pressure, either in cavity molds to provide a plurality of individual railway ties, or in a continuous mold, followed by subdivision of the molded product into a plurality of individual railway ties.
• railway ties having excellent properties can be made in a continuous process on a production line illustrated in the schematic drawing of the Figure.
• Each production line requires two heated auger processors (one for Formula I and one for Formula II) and each auger processor is fed by a batching hopper feeding into two blenders.
• the plastic (and in the case of Formula II reinforced plastic) component and the granular asphalt component are charged into a batching hopper in the desired relative amounts, whence they are fed into rotating blenders to produce the plastic/asphaltic mixture which is fed into the processor.
• the raw materials for the plant process of the present Invention comprise two kinds of thermoplastic - typically polyethylene and polypropylene - in the form of pellets, flakes, etc. and crushed asphalt pavement.
• Plastic pellets are typically delivered in gaylords or in bulk, via truck or rail transport. Gaylords of plastic pellets are normally unloaded into onsite or shipping containers by the application of vacuum, or by tipping and gravity feeding into a receiving hopper or bin.
• the crushed asphalt used in the formulation is typically delivered in 25 to 60 ton dump truck loads.
• the three raw materials are delivered to the plant pre- processed ready to mix together in accordance with the formulas described above.
• a preliminary blender which may incorporate preheating means to dry the mixture, mixes Formula I or Formula II components to a homogeneous dry consistency and, on demand, continuously feeds that mix to the dedicated DUROPARTM heated auger processor at a rate dictated by the speed of operation of the processor.
• each production line includes two such processors and each processor requires two blenders to maintain a steady flow of mixed materials to the respective auger processors.
• the DUROPARTM processor used in the method of the invention is, in effect, a heated auger mechanism having a rotating screw inside a barrel of a length from 6 to 15 feet.
• the role of the heated auger in combining plastic and asphalt to produce Formula I or Formula II is three-fold:
• the metal barrel encasing the auger is heated to a suitable temperature, depending upon the mix being processed, but typically between about 320 0 F and 550 0 F.
• the objective is to heat the plastic/asphalt mix itself to the melting temperature of the plastics.
• the melting range of thermoplastic materials useful in this invention will be roughly in the range of from 300 0 C to 34O 0 C
• a gradient of temperatures zones is maintained in the processor, so that there is a higher temperature where processing and discharge of the formula is under way, to speed up heat transfer to the material, with a lower temperature maintained while the processor is idle. It is important to note that the Formula I blenders feed the Formula I auger processor while the other blender is being refilled or the mixture is being blended in the batching hopper blenders, and conversely. That is to say, one blender is filling or mixing while the other is feeding.
• the semi-fluid composite exiting from the processor is fed into a pump which injects the formula at about 2000 ps ⁇ . through a conventional "dual material" die into a flow mold (tie mold).
• the flow mold both shapes and cools the composite until it stabilizes enough to emerge from the mold.
• the process is analogous to extrusion molding in plastics technology.
• the tie can be textured, to better grip the ballast the tie will be laid on and decrease movement of the tie once installed.
• the texturing is typically administered to three sides of the tie, so that the top side, to which the rail is attached, remains smooth.
• Texturing can be in any suitable pattern, for example, a diamond pattern, and can use any texturing means.
• texturing of the tie can be through the embossing of a pattern onto the tie using one or more embossing wheels, which are subject to heat and which rotate as the tie is passed through them. Texturing can also be through a stamping process.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Polymers & Plastics (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Organic Chemistry (AREA)
• Mechanical Engineering (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Architecture (AREA)
• Materials Engineering (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Moulding By Coating Moulds (AREA)

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• 2010
  • 2010-02-26 RU RU2011139327/05A patent/RU2540641C2/ru not_active IP Right Cessation
  • 2010-02-26 WO PCT/CA2010/000245 patent/WO2010096911A1/en active Application Filing
  • 2010-02-26 US US12/713,850 patent/US8252216B2/en not_active Expired - Fee Related
  • 2010-02-26 EP EP10745762A patent/EP2401330A4/de not_active Withdrawn
  • 2010-02-26 CA CA2784337A patent/CA2784337C/en not_active Expired - Fee Related

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